William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What are the symptoms of low libido?

The person that lacks sexual desire won't want to initiate the sexual relation. If the act is initiated, low libido can also present itself as the inability to attain an erection. If the patient experiences a first episode of erectile dysfunction without any previous sexual symptoms and adequate nocturnal erection, the cause is probably psychogenic and the problem is not the erection. It is also important to specify if the low libido is new in onset or if one has always felt this way about sexual relations.

What is erectile dysfunction?

Erectile dysfunction (ED) is the inability to acquire or maintain a satisfactory erection. The prevalence of erectile dysfunction varies according to the patient's age. About 18% of men from 50 to 59 years of age will suffer from erectile dysfunction and 37% of those aged 70 to 75 years will, too.

There are three types of erections -- those caused by tactile stimulation, those caused by mental stimulation, and those that men experience while sleeping. This classification can be important when the cause of erectile dysfunction is yet to be determined.

In order to have an erection, men need stimuli; they need blood arriving from the arteries and a veins capable of locking the blood in place. Each of the numerous steps in this system can fail making erectile dysfunction a complex problem for investigation.